String instrument



Oct. 1952 F. MACHALEK STRING INSTRUMENT I Filed April 12, 1949 PatentedOct. 21, 1952 UNITED STATES PATENT OFFICE Application April 12, 1949,Serial No. 87,045 Iniczechosloyakia April 12, 19 48:

61' Claims. 1

Stringed musical instruments are generally providedwith a. set ofindividual strings, which are :tuned to azcertain frequency andactuatedin any known :way either. to produce sounds which are directly audibleor to vibrate mechanically in a frequency range corresponding.v toinaudible sounds, in which case such vibrations are picked upelectrically, electrostatically or electromagnetically andreproduced bymeans of. an. amplifier supplying a loud speaken.

Instruments of such a kind must be. rather frequently. tunedto keeptheir oscillating frequencies. on/the. desired value. especially if thestrings'are. of different material and thickness and iftheyare subjectto changes of temperature or moisture content inthesurrounding air.

Itis an object ofthe. invention to provide such an. instrument, wherethetuningof the strings maybe either completely eliminated or at leastreduced to ameasure, where the wholetuning may be carried out quicklyandv more accurately.

In..accordance...with. known physical laws, the oscillating frequencyofa string is directly proportional tov the square. root of its tensionand indirectly, proportional. to the length of. the string and to thesquareroot of its mass. If a single stringis used, thediiferent partsofwhich are used for generatingdifierent frequencies, and an equal.tension of the different string parts is kept, themass. remains equaland. the resulting frequency is only. indirectly proportional. to thelength of the respectivestringpart.

The invention isby. way. of example shown diagrammatically, in theaccompanying drawing, showing. in Fig. lone suitable. arrangement, inFig. 2. a detail of an arrangementof the bridge, in Figs. 3" and'4'otherembodiments of the invention.

In the arrangement'shown in Fig. l a, string ,3 is stretched between twoframe parts'I; 2 over two sets of rollers a1, a2, a3. a4 and b1, be, be,D4. The string 3' is fixed at 4 on the frame I and is guidedconsecutively overthe rollers b1. .121, D2 and soon until his"fixed'either" below the. roller a4 upon a'tuning' key, or tea weight'orany other force acting upon the end of the'string'. The distancesbetween'the two sets of rollers are such,

that the" lengths of the" respective string parts stretched byy'aforceadditionallyreduced by the friction of rollerbi; and so on.

Anequalization of. the stretching: forces may be obtained by-sounding,the strings, whereinsthe oscillations producedpractically perfectlyequalize'the tension of all the stringparts.

If one frame part is used, where the line connecting the centres oftherespectiveroller set is perpendicular to the; stringparts, twostrlngparts are always of the same length. If it is desired that every stringpart should cover a different tone, it is necessary toprovide bridgesv101,122 p8 near one of the roller sets. As the angle, by whichthestringpasses over the bridge.

does not differ much from the pressureof.

thestring upon. the bridge issmall, so thatthe bridges do notsubstantially increase the friction.

To make the equalization of. the tension of different string partseasier, it is possible to bring said bridges out offcontact with thestring portions just for the time necessary for the equalization ofthetension which may be carried out, for instance,,by sounding, thestrings. An example of such an arrangement/is shown diagrammatically inFig. 2.

The framepartZ carries theroller I), over which the string .3'isstretched in the manner as described with reference to Fig. l. Thebridge p is arranged on ledge 5 held by'a bracket 6, fixed by means ofhinges I to the frame 2. A helical spring B'Qctingupon this bracket'fiand guided by. thebolt I, provided. with a nut, is pressing this bracketagainst the frame 2 and brings simul taneously the bridge p in'engagement 'with the string 3'. By'overcoming' the pressure of thespring 8 by acting upon the bracketfiin th'e'direction ofthe'arrow',.the bridge"p may be removed from engagement withthe string.After equalizationof the tension of the'different string parts, thebridges '10 may be again broughtinto engagement withthestring 3.

Instead of the string 3 being fixed atone end and stretched bysomeforce-at the otherend, it "is possible to fixboth ends of the string onone frame part, carrying one set of rollers. Fig. 3 showssuch anarrangement. The'frame'parts I and '2 each carry'one'of the roller'setsa and b respectively. The-ends of thestring- 3-are fixed at the points 4and 10 on the-frame part I. The bridges p1, p2 of the frame part 'Iwhich is'slidable against the frame part 2 in the direction of the pullof the strings. The frame partZ'is fixed whileon the frame part I aforce Facts in the" downward direction to stretch the respective stringparts. In some cases this force P may berepresented by the weight of theframe part I with its'accessories. Thus the" same effect may be'obtalned as m are arranged on'extensionsin Fig. 1, but the effect ofthe frictional resistance of the rollers is minimized, and both ends ofthe string are fixed.

Instead of using two frame parts one of which is slidable with respectto the other in the direction of the pull of the strings, both frameparts may be arranged pivotally with respect to each other and heldapart by a stable force. Fig. 4 shows such an arrangement. The frameparts I and 2 carry again each one roller set a and b respectively. Bothframe parts I and 2 are pivotally connected and may be turned around thepivot II. The ends of the string 3- are fixed in the places 4 and It onthe frame part i and guided consecutively over the roller sets a and b.Bridges p1 pa are arranged on an extension of the frame part I and aforce P acts in the direction of the indicated arrows to hold both frameparts apart. In other respects this arrangement acts in the same Way asthe arrangement described in the foregoing. It is to be noted that whilein Figure 3 one frame part is slidably arranged with respect to theother, whereas in Figure 4 such frame parts are pivotally connected toeach other, the common character of both these frames resides in thatthe said parts are collapsably arranged with respect to each other.

The bridges pi, 192 shown in Figs. 1, 3 and 4, may be replaced byrollers, thus reducing still more their effect upon the tension of thestring and providing fo' more easily equalizing the tension.

When using a string stretched according to any of the methods described,it is possible to change the pitch of all strings simultaneously byincreasing or decreasing their tension, whereby the ratio of theirlengths remains constant. The sounding of the strings may be done in anyknown way, for example, by a keyboard.

t is obvious, that the arrangement as described may be changed in manyways within the scope of the invention. It is, for instance, possible touse no bridges at all and arrange the rollers at such a distance, thatthe distances between the rollers determine the length of the individualstring parts only. If each string 1: rt has to be used for a differentfrequency, the connecting lines of the centers of the rollers must notbe at a right angle to the respective string parts. Instead ofindividual bridges a common bridge may be used for all parts of astring. Similarly there may be the possibility of adjusting the activelength of each string part by adjusting the position of the bridge.

All of the above discussed embodiments are considered to be understoodby those skilled in the art to which the present invention is acontribution.

Instruments of this kind show a high degree of stability, the differentstring parts are influenced by outside conditions in the same way, sothat they react to those influences equally and said string parts do notbecome mutually out of tune by any changes of moisture of the air, or bydifferences of temperature. The tuning if required at all is donequickly and effectively.

Having now particularly described and ascertained the nature of my saidinvention, and in what manner the same is to be performed, I declare,that what I claim is:

1. A string instrument, comprising in combination, a frame including twoparts pivotally connected to each other; two sets of rollers arranged onsaid parts, respectively, opposite to each other, the distances betweena roller of one of said sets and the opposite roller of the other one ofsaid sets forming an increasing progression; a string having the endsthereof secured to one or" said parts and forming a zig-zag lineengaging alternately a roller of one of said sets and a, roller of theother one of said sets so as to be subdivided into succeeding ortionshaving increasing lengths; and means for exerting a force on said partsof said frame urging said parts asunder whereby the portions of saidstring are tensioned so as to produce frequencies in the ratio of thelengths of the portions of said string.

2. A frame for use in a, stringed musical instrument, comprising twodistinct parts adjustably arranged with respect to each other, two setsof rollers rotatably arranged on said parts, respectively, opposite toeach other, the distances between a roller of one of said sets and theopposite roller of the other one of said sets forming an increasingprogression, a vibratable string having both its ends secured to one ofsaid parts and forming a zig-zag line engaging alternately a roller ofone of said sets and a roller of the other one of said sets so as to besubdivided into succeeding portions having lengths corresponding totheir frequencies of vibration and means for simultaneously stretchingall of said portions so as to produce frequencies in the ratio of thelengths of said portions.

A frame for use in a stringed musical instrument, comprising twodistinct parts adjustably arranged with respect to each other, one ofsaid parts carrying a pm at one of its ends and a tuning key at itsother end, two sets of rollers rotatably arranged on said parts,respectively, opposite to each other, the distances between a roller ofone of said sets and the opposite roller of the other one of said setsforming an increasing progression, a vibratable string having its endsfixed on said pin and on said key, respectively, and forming a zig-zagline engaging alternately a roller of one of said sets and a roller ofthe other one of said sets so as to be subdivided into succeedingportions having lengths corresponding to their frequencies of vibration.

4. A frame for use in a stringed musical instrument, comprising twodistinct parts collapsably arranged with respect to each other, two setsof rollers rotatably arranged on said parts, respectiveiy, opposite toeach other, the distances between a roller of one of said sets and theopposite roller of the other one of said sets forming an increasingprogression, a vibratable string having both its ends secured to one ofsaid parts and forming a zig-zag line engaging alternately a roller ofone of said sets and a roller of the other one of said sets so as to besubdivided into succeeding portions having lengths corresponding totheir frequencies of vibration and means for exerting a force on saidparts of said frame urging said parts asunder whereby the portions ofsaid string are tensioned so as to produce frequencies in the ratio ofthe lengths of the portions of said string.

5. A frame for use in a stringed musical instrument, comprising twodistinct parts arranged for translatory motion with respect to eachother, two sets of rollers arranged on said parts, respectively,opposite to each other, the distance between a roller of one of saidsets and the opposite roller of the other one of said sets forming anincreasing progression; a string having the ends thereof secured to oneof said parts and forming a zig-zag line engaging alternately a rollerof one of said sets and a roller of the other one of said sets so as tobe subdivided into succeeding portions having increasing lengths, andmeans for exerting a force on said parts of said frame urging said partsasunder whereby the portions of said string are tensioned so as toproduce frequencies in the ratio of the lengths of the portions of saidstring.

6. A frame for use in a stringed musical instrument comprising twodistinct parts collapsably arranged with respect to each other, two setsof rollers rotatably arranged on said parts, respectively, opposite toeach other, the distances between a roller of one of said sets and theopposite roller of the other one of said sets forming an increasingprogression, a vibratable string having both its ends secured to one ofsaid parts and forming a zig-zag line engaging alternately a roller ofone of said sets and a roller of the other one of said sets so as to besubdivided into succeeding portions having lengths corresponding totheir frequencies of vibration, bridges ar- REFERENCES CITED Thefollowing references are of record in the file of this patent:

FOREIGN PATENTS Number Country I Date 2,512 Great Britain June 5, 1801304,862

Germany Apr. 12, 1918

